Device for producing hot air.



J. SCHLATTER.

DEVICE FOR PRODUCING HOT AIR.

APPLICATION FILED N0v.29, ISIS.

Patented Apr. 22,1919.

'ai eras ran @FME , taxon scHLAr'rnn, or ZunIcH, SWITZERLAND, .assrenon'ro scr-ricamare rnona'rn a eo., or Zoon, SWITZERLAND.

Specification of Letters Patent.

Patented Apr., 22, M3919,

' Application ledl November 29, 1918. Serial No. 264,725.

To all wkofmfz't may concern:

Be it known that l, JAKOB SCHLATTER, a citizen of the Republic ofSwitzerland, residing at Zurich, .Baumgasse`10, Switzerland, haveinvented new and useful lmprovements in Devices for Producing Hot Air;and I do hereby' declare the Vfollowing j to be a clear, full, and exactdescription of the invention, such as will enable others skilled in theart to which it appertains to make and use the same, reference vbeinghad to the accompanyin drawings, and to vletters or figures of referencemarked thereon, which form a part of this specification.

rlhis invention relates to a device for producing hot air adapted to beused, for instance, in drying installations for such products that haveto besubjected to preliminary drying and to final drying at giventemperatures. These products include fruits, vegetables, cosmetic andchemical products, sensitive dyes, etc., for which a drying process atgiven temperatures or within given limits of temperature is a necessarycondition.

Devices for producing hot air are already Y.

known in which a mixture of Hue gases and fresh air produced in afurnace is caused to pass previous to its entering into the installationwhere the dry air is to be used through at least one strainer, wiregauze' or a similar metallic surface acting as a Hue dustandsoot-catcher. Such devices have, however, the drawback, that the Huedust and the soot contained in the mixture are not wholly caught up bythe Wire gauze, strainer or the like, so that `a pa-rt of the dust andsoot is conveyed to the drying installation where they act in a verydetrimental manner upon the products to be dried. ln such devices theWire gauzes, the strainers or the like are moreover lsoon clogged by theHue dust which reduces to a considerable amount the quantity of airpassing through the dustand soot-catcher. A further disadvantage of saiddevices proposed hitherto consists in that the wire gauze, strainer orthe like is very soon destroyed by the hot Hue gases coming in contacttherewith.

The object of the present invention is to provide a device for producinghot air comprising a fan drawing the hot gases generated in a furnacethrough at least one filter chamber in which said hot gases are at firstbacked up and then caused to pass through tering material.

at least one layer of a Hltering material adapted to catdlt up the Huedust and soot, whereby the bottom of said Hlter is continuously cooledby the fresh air streaming un,- derneath the filter past the latter intoa mixing chamber. The filter chamber is provided preferably "within theupper portion of the furnace and the filter consists of one or morehorizontally arranged layers of Hlen requisite, tlhe filter may besubdivided, into a plurality. of cells, and the layer or layersrespectively of the filter may consist of refractory material put on abottom or support permeable to gas. ln some cases it is advantageoustoprovide in connection with the filter adjustable pres'- sure members inorder to press the Hltering material near the edges of the filtertightly against the adjabent walls of the furnace.

The invention consists also in the particular construction, arrangement,and combination of parts as will hereinafter be fully set forth, andpointed out in the claims, reference Ibeing [had to the accompanyingdrawings, in which:

Figure l is a vertical longitudinal section through a first constructionaccording to this invention;

Fig. 2 is a cross-section on the line llf--ll of Fig. 1;

Fig. 3 is a similar cross-section drawn on an enlarged scale through asecond embodiment of the invention, and

Fig. 4 shows diagrammatically a device comprising a Hlter chambersubdivided into a plurality of cells.

Referring at first to Figs. 1 and 2, l denotes a cylindrical jacketsurroundin a, furnace for producing hot air. This has a cylindricalcasing 2, a rate 3 and an ash pit 4. 5 designates the re door ofthefurnace and 6 a pivoted valve by means of which admission of air fromthe to into the interior of the furnace can be regu ated.

In the interior ofthe upper portion of the furnace jacket l is providedthe filter chamber 7 lcommunicating with the interior of the cylindricalcasing 2 by means of a short conduit 8 of annular cross-section.Opposite the .outlet opening of said conduit 8 is provided a baflieplate 9. Between the latter and the conduit 8 is rovided a wall havingapertures 10.. he

lower part of the filter chamber' 7 is formed by a horizontal bottom -llpermeable urnace to gas and consisting of perforated sheet iron or wiregauze or the'like. On this bottom 11 is put for( instance a layer ofsmall pieces -of Hre bricks (chamotte) obtained by breaking'ire bricksto small pieces having a diameter of about 10 to 15 millimeters. On thislayer of .fire Vbricks is put a second layer of such pieces havinghowever a diameter of Aonly about 4 to 8 millimeters. When requisite, afurther layer of dust of fire bricks may be put on1 said second1 layerof small pieces of Hre bricks. Better 'results are obtained, however,by' laying on the uppermost layer of fire brlck pieces a layer of-aboutone centimeter thickness of asbestos fabric or asbestos wool. The Hrebricks broken to small pieces (also other refractory ma.

terials may be used when requisite) have a rough surface on which theHbers of asbestos cling easily and which provides for an intimateconnection of the diH'erent' layers of the filter, so that the latterare not loosened or shifted relatively to one another when the hot gasespass through the filter. Thus any formation of apertures in the filterwhich would provideA for avdirect assage of the gases through it, isprevented.

The Hlter chamber communicates through the layers 12 with a mixingchamber 13, while for the rest it is closed on all sides. Laterally ofthe mixing chamber 13 is provided a fan 14 and it communicates with theatmosphere by means of apertures controlled by slides 15 andan annularconduit 16.

The operation of the device described is as follows: The hot Hue gasesproduced in the furnace are drawn by the fan 14 through the conduit 8and the apertures 10 into the Hlterchamber 7 where they accumulate orbackup in front of the iltrating layers 12. The gases are thus subjectedin front' of the filter proper to a certain pressure in the upperportion of the chamber 7 where the temperature rises up to 700 and even10001200 C. The Hue gases. are then caused to pass from the upperportion of the chamber 7 downward through the different Hltrating layers12 which catch up the Hue dust, the soot and other only partially burntparticles which. may be con- 4tained in said gases. The latter passhereupon into the mixing chamber 13 and from the latter into the fan 14.The Hue gasesmix in the chamber 13 with fresh air passwhich it ispreheated.- vSaid fresh air cools the bottom 11 while it passes from theleft to the right through the upper portion of the furnace into themixing chambenso thatv said bottom is not destroyed by the red heattemperature existing in the upper portion of the chamber 7 1nconsequence'of this, any sagging of the Abottom that the filtering-massresting thereon does 11 is prevented, so4

4not change its position and formation of Hltrating layers 12 have giventhe surpris# ing result that said gases do not only contain any soot andHue dust, but also only a small percentage of carbon monoxid, a verysmall quantity of sulfurous acid and nosulfuric anhydrid. This proves,that the .iltrating layers 12 do not only act as a mechanical means forcatching up the Hue dust and soot, but are also adapted to bring aboutsome chemical reactions. These 'rej actions are -a consequence of theheating of the Hltrating mass due to the backing up of the furnacegasesgin front of said mass causing a heating of the Hltrating layers upto 10001200 C. The highly heated Hltrating mass acts then as a Contactmass effecting a disassociation of the water vapor H2O into Hz-f-O. Theoxygen thusset free is then very active and brings about certain veryimportant chemical reactions. Thus, all the carbon, z'. e. thesoot,.contained vin the Hue. gases is wholly burnt, the carbon monoxidcombines with the oxygenset free to CO2. It has also been found, thatthe oxygen set free acts in such a manner upon the ltrating mass and(gases that carbonates,

such as A1,(CO3), aCO3, MgCO3, etc. and sulfates, such as CaSO4, MgSOMFeSO4; Fe2(SO4), A1,(SO4)8 are formed.

The possibility of regulating the temperature Within the Hlter' chamber7 in the manner above mentioned renders the device more fire proof, asany sudden, great and conseguently dangerous increase of temperature 1sprevented.

In vthe construction of the invention illustrated in Fig. 3, where theparts 1-11 corl respond substantially to the parts designated with thesame reference number of the first described embodiment, the bottom 11is mounted on a frame 13 supported by the jacket 1. 14 denotes apivotally mounted cover for the Hlter chamber 7. 15 and 16a are railshaving an L-shaped cross-section. These rails are arranged .so that therails 16*L are Hush with lthe outer circumference of the layers 12 olfthe lter, while the rails 15a are Hush with the inner circumference ofsaid layers 12. 17 are angle-irons Hxed toI the inner wall of thechamber 7 and to the outer wall ofthe pieces provided with the apertures10 respectively. Said angle-irons 17 act as supports for screwthreadedbolts 18 provided on their lower l end with a pressure head resting on arail 15 or 16a respectively. 19 designates vapertures which are foradmitting fresh air and which can'be covered to any desired amount bymeans of adjustable slides 20. I

Upon a tightening of the screw threaded bolts 18, the. rails 15a, 16aare pressed I againstv the upper layer of the filter which is thenpressed tightly against the walls of the frame 13a. As a result of this,any air passages still present between the layers `of the filter and theframe 13a and which would admit a are filled out. onsequently, all fiuegases streaming in the direction of the arrows A are caused to passthrough the layers 12 of the filter.

As illustrated diagrammatically in Fig. 4, the filter can be subdividedinto a plurality of cells 2-1. ln connection with each such cell aseparate pressure device may be pro- 15 vided, so that the material ofthe filteriof each single cell4 can be pressed together to the requiredamount independently of the r material of the other cells.

in a device for producing hot air designed 20 according to thisinvention, the following advantages are obtained besides those alreadymentioned: in such a device not the whole mixture of flue gases andfresh air is purified, but only the flue gases. As a result of this, thesize of the filter can be `chosen relatively small. Owing to the veryhigh temperature present within the filter chamber and the bettercombustion obtained,

' the hot air produced in the new device contains fewer noxious gasesthan the hot air produced in the devices proposed hitherto;

this .is of considerable'importancein several' respects. A furtheradvantagey of the device according to this invention consists in thatthe fiue gases are caused to pass downl ward through the filter, so thatthey tend to press its layers toward the bottom 11; keeping thereby thelayers of the filter together andpreventing a formation of holes 40therein.

Having thus described my invention, what I `claim as new, and desire tosecure by Letters Patent, is:

1..-A device for producing hot air, comprising a furnace for heatingair, a fan arranged next to said furnace, a chamber, and means containedin said chamber acting as a filter for the flue dust and soot containedin the fiue gases produced in the furnace, said chamber being arrangedso that the fiue gases are caused to pass downward through the filteringmeans contained in said chamber before they are drawn into the fan andthat said gasesbacking up in front of the filtering means cause a greatincrease of temperature in-'said chamber and highly lheat the filteringmeans.

' 2. A device for producing hot air, comprising a furnace for heatingair, a fan arranged next to said furnace, a chamber provided in theupper portion of the furnace, filtering means contained insaid chamber,and a conduit connecting the combustion space of the furnaceto saidchamber, the flue gases produced in the furnace being drawn assage ofthe flue gases,.

by the fan at first intothe upper portion of said chamber, where theyback up, then downward through the filtering means and finally into thefan itself, the backed up gases causing a great increase of temperaturein said chamberand heating the filtering means to a high degree.

3. A device for producing hot air, comprising a furnace4 for heatingair, a fan arranged next to said furnace, a chamber provided in theupper portion of said furnace,

a metallic member permeable to gasy form:y ing the bottom of saidchamber, filtering means in horizontal layers on said bottom,

a conduit connecting the combustion space of the furnace to said chambercontaining the filtering means, a mixing chamber provided between thebottom of the filter chamber and the fan, 4and conduits connecting saidmixing cham'ber with the atmos- 85 phere, the fiue gases produced in thefurnace being drawn by the fan at first into the upper portion of thefilter chamber where they back up before the filtering means, thendownward through the filtering means into the mixing chamber and finallyinto the fan itself. 4

4. A device for producing hot air, comprising a furnace for heatingair,a fan ar ranged next to said furnace, a filter chamber provided in theupper portion of said furnace, a vmetallic member permeable to gasforming the bottom of said chamber, filtering means in horizontal layerso n said bottom, a conduit connecting the combustion space of the'furnace to said filter chamber, a mixing chamber provided between thebottom of the Ifilter chamber and the fan, and means for supplying freshair to the mixing chamber so arranged that the supplied air cools saidbottom of the filter chamber, the gases produced in the lfurnace beingdrawn by the fan at first into the upper portion of the filter chamberwhere they back up before the filtering means, then downwardl throughthe filtering means into the mixing chamber and finally into the fanitself.

5. A device for producing'hot air, comprising a furnace for heating air,a fan arranged next to said furnace, a chamber hav- 115 ing a bottompermeable to gas, a conduit connecting the combustion space of thefurnace with said chamber, pieces of porous refractory material ofdiHerent; size on said bottom actin as a filter for the fiue dust and120 soot contalned in the flue gases produced in the furnace, saidchammr being so arranged 'that the fiue gases pass downward through therefractory substance before fthey are drawn into the fan and back up infront of the filtering means thereby causing a great increase oftemperaturetin said chamber and highly heatingthe filtering means.

6. A device for producing hot air, coni-1 prising a furnace for heatingair, a fan ari vranged next vto said furnace, a chamber havon said brickpieces, the layers of brick pieces and asbestos acting as a filter forthe Hue dust and soot contained in the flue gases produced in thefurnace, said chamber being so arranged that the Hue gases are caused topass downward through the filter before they are drawn into the fan,whereby the gases back up in front of the filter causing thereby a greatincrease of temperature in said chamber and heating the fire bricks to ahigh degree.

7. A device for producinghot air, comprising a furnace for heating air,a fan arranged next to said furnace, a chamber having a metallic bottonipermeable to gas, a conduit eHecting a communication between thecombustion space of the furnace and said chamber, layers of small brickpieces of different size on said bottom, a layer of asbestos on saidbrick pieces, the layers of brick pieces and asbestos acting as a filterfor the ue gases produced in the furnace, a mixing chamber arrangedbetween said metallic bottom and the an, and conduits supplying freshair to the mixing chamber, the fresh air entering into the lattereHecting at the vsame time a cooling of said metallic bottom, and saidfirst mentioned members being so arranged that the Hue gases are causedto pass downward through the filter before they are drawn into the fan.

,8. A device for producing hot air, comprising a furnace for heatingair, a fan arranged next to said furnace, a chamber having a bottompermeable to gas, Hltering means on said bottom, the combustion space ofthe furnace with said chamber, and adjustable pressure means adapted toexert a pressure upon the filtering means to press the latter tightlyagainst the walls of said chamber which is so arranged that the Huegases produced in the furnace are caused to pass downward through thefiltering means before they pass into the fan.

a conduit connecting vided in the upper portion of said furnace,

a conduit connecting the combustion space Yof the furnace to saidchamber, a frame arranged within said chamber, a bottom permeable to gasresting on said frame, filtering means on said bottom, rails laid on thefiltering means near the edges of the frame, and adjustable means forpressing the rails against the filtering means, said chamber being soarranged that the Hue gases produced in the furnace are caused to passdownward through the filtering 'means before they are drawn into thefan.

10. The combination with a furnace, of a receptacle to receive the Huegases and'dust therefrom, a filtering medium in the receptacle operatingto back up the gases therein and thereby increase the temperature in thereceptacle and highly heat the filtering medium, means to draw the gasesthrough the latter, and means whereby the overheating of the receptacleby the filtering medium is prevented.'

11. The combination with a furnace, lof a receptacle to receive the Huegases and dust therefrom, `a filtering1nedi um in the receptacleoperating to back up the gases therein and thereby increase thetemperature in the receptacle and highly heat the filtering medium,means to draw the gases throughthe latter,and means including the lastnamed means whereby a current offair is passed under the receptacle toreduce the temperature of the latter. y v

12. The combination with a furnace, of a receptacle, a filtering mediuminthe bottom thereof, means to admit Hue gases and dust from the.furnace into the receptacle abovel the filtering medium, means to.admit fresh air beneath the bottom' -of the receptacle, a mixingchamber, andasuction device to draw air from beneath the receptacle andgas through the filtering medium into'the mixing chamber, for the urposespecified.

In testimony that I clalmthe foregoing as my invention, I have signed myname.

JAKOBISCHLATTER.

